Microvascular anastomotic thrombosis in experimental diabetes mellitus.

An experimental model was developed to investigate the effects of glycemic control and pentoxifylline administration on microvascular anastomotic patency rates in streptozotocin-induced diabetic rats. Diabetes was confirmed by blood glucose levels of more than 300 mg/dl prior to administering insulin and/or pentoxifylline. Microvascular anastomoses of the femoral artery and vein were performed 4 weeks after induction of diabetes. Subsequently, the comparative rates of anastomotic thrombosis in diabetic and nondiabetic groups with or without insulin or pentoxifylline administration were assessed by direct visualization of the anastomotic sites after 4 days. The results suggest that hyperglycemia impairs the post-operative patency of microvascular venous anastomoses. The diabetic animals maintained under insulin regimens that tightly controlled their serum glucose levels (100 to 200 mg/dl) experienced patency rates similar to those of nondiabetic controls (p < 0.05). Pentoxifylline improved microvenous patency at all levels of hyperglycemia studied, suggesting a possible hemorrheologic mechanism for microvascular venous anastomotic thrombus formation in diabetic animals.